A coil constituted by a wound wire is typically formed on a magnetic pole of a multi-pole armature. A conventional method of forming the coil uses an apparatus known as an inserter. In the method using the inserter, first, a coil having a predetermined shape is formed by winding the wire around a flyer or the like. Next, the coil is dropped between blades disposed below the flyer and inserted by an insertion jig into a slot formed in an inner peripheral surface of a stator. Further, using a shaping jig, the coil is housed securely in the slot, whereupon coil end portions projecting from respective axial direction ends of the stator are shaped. Finally, the coil is fixed by being tied using string or the like.
In the method described above, however, the steps required to perform winding are complicated, leading to a reduction in the productivity of the stator coil. Furthermore, when, in the method described above, the coil is inserted into the slot, the coil is likely to be damaged in particular by coming into contact with an edge portion of the stator. Hence, in the method described above, to avoid damaging the coil, the coil is inserted with a certain amount of leeway. However, when the coil expands such that a coil length becomes longer than necessary, an excessive amount of the coil projects from the end portions of the stator, leading to an increase in an axial direction length of the stator. Further, the excess part of the coil has no effect on the characteristics of the coil, leading to a reduction in the characteristics of a motor.
JP08-308188A discloses, as a method for solving these problems, a winding method for winding a wire around a slot by repeatedly performing the steps of: latching one end of a wire fed from a nozzle to a predetermined location and then causing the nozzle to project from a second end side of a stator between adjacent slots; hooking the wire fed from the nozzle onto a tip end of a hook on the second end side of the stator and then moving the hook with the wire hooked thereon around a periphery of the stator; separating the wire from the hook in a position straddling a predetermined number of slots, and then dropping the wire between adjacent slots; causing the nozzle to retreat to a first end side through between the slots into which the wire has been dropped; and moving the retreated nozzle around the periphery of the stator to return the nozzle to its original position.